Main characteristics
Characteristic | Meaning |
Designation: | |
Engines without turbocharger | F8Q 620, F8Q 788* |
Engines with turbocharger: | |
Indirect injection - 1.9 dT models | F8Q 784, F8Q 786* |
Direct injection - 1.9 dT models | F9Q 730, F9Q 734* |
Cylinder diameter | 83.0 mm |
piston stroke | 93.0 mm |
Working volume | 1870 cm3 |
Compression ratio: | |
F8Q engines without turbocharger | 21.5:1 |
F8Q engines with turbocharger | 20.5:1 |
F9Q engines | 18.3:1 |
The order of operation of the cylinders | 1-3-4-2 (#1 cylinder on the flywheel/drive plate side) |
Direction of rotation of the crankshaft | Clockwise as viewed from pulley side |
* Engines without intermediate shaft. |
Compression (engine warm - approx. 80°)
Characteristic | Meaning |
Normal pressure: | |
F8Q engines | 27 bar |
Minimum Pressure - All Engines | 20 bar |
Maximum difference between cylinders | 4 bar |
Valve clearances (engine cold)
Characteristic | Meaning |
Inlet valve | 0.20 mm |
Exhaust valve | 0.40 mm |
Toothed drive belt tension (see text)
Characteristic | Installation/Check | Minimum |
F8Q engines with timing belt "HTD" and F9Q engines | 38±10% by SEEM block | 36 by SEEM block |
F8Q engines with timing belt "HTD2" | 47±10% on the SEEM block | 36 by SEEM block |
Cylinder head
Characteristic | Meaning |
Height: | |
F8Q engines | 159.50±0.20 mm |
Maximum allowable deformation of the gasket surface | 0.05mm |
Swirl Chamber Protrusion - F8Q Motors | 0.01 - 0.04 mm |
Depth of the valve in relation to the surface of the cylinder head: | |
Inlet | |
Engines without turbocharger | 0.85±0.09 mm |
High school graduation | |
Engines without turbocharger | 0.97± 0.09mm |
Valve seat angle: | |
Inlet | |
F8Q engines | 120° |
High school graduation | |
F8Q engines | 90° |
Valve guide inner diameter: | |
F8Q engines | 8.00 mm |
Valve guide outer diameter: | |
F8Q engines: | |
Nominal | 13.00 mm |
F9Q engines: | |
Nominal | 12.00 mm + 0.03 mm - +0.05 mm |
Camshaft
Characteristic | Meaning |
Axial clearance | 0.05 - 0.13 mm |
Valves
Characteristic | Meaning |
Head diameter: | |
Inlet | |
F8Q 620 and F8Q 788 engines: | |
regular saddle | 36.100 mm |
F8Q 784 and F8Q 786 engines | 36.225±0.125 mm |
F9Q engines | 35.200 mm |
High school graduation | |
F8Q 620 and F8Q 788 engines: | |
regular saddle | 31.500 mm |
F8Q 784 and F8Q 786 engines | 31.620±0.120 mm |
F9Q engines | 32.500 mm |
Rod diameter: | |
F8Q 620 and F8Q 788 engines | 8.000 mm |
F8Q 784 and F8Q 786 engines | 7.985±0.040 mm |
F9Q engines | 7.000 mm - 0.010 mm - 0.020 mm |
Valve spring free length: | |
F8Q 620 and F8Q 788 engines | 43.41 mm |
F8Q 784 and F8Q 786 engines | 47.57 mm |
F9Q engines | 45.80 mm |
* Cylinder heads with steel valve seats may be identified by ribs on them.
Cylinder block
Characteristic | Meaning |
Cylinder valve diameter: | |
Class A or 1 | 80.000 - 81.015 mm |
Class B or 2 | 80.015 - 80.030 mm |
F9Q Engines - Rating | 80.000 mm |
* Cylinder size classes are indicated by holes on the side of the block, directly below the cylinder head seat. |
Pistons and piston rings
Characteristic | Meaning |
Piston ring gaps (pre-installed) | |
Piston ring thickness: | |
Top compression ring: | |
Engines without turbocharger | 2.0 mm |
Engines with a turbocharger | 2.5mm |
Second compression ring | 2.0 mm |
Oil scraper ring | 3.0mm |
Clearance between piston and cylinder wall | 0.015 - 0.030 mm |
Connecting rods
Characteristic | Meaning |
Working clearance of connecting rod bearing | 0.014 - 0.053 mm |
Side play of the connecting rod cap | 0.220 - 0.400 mm |
intermediate shaft | |
Axial clearance | 0.07 - 0.15 mm |
Crankshaft
Characteristic | Meaning |
Main bearing journal diameter: | |
F8Q engines: | |
Nominal | 54.795±0.01 mm |
F9Q engines: | |
Nominal | 54.790±0.01 mm |
Operating clearance of the main bearing | 0.020 - 0.058 mm |
Connecting rod journal diameter: | |
F8Q engines: | |
Nominal | 48.00 mm |
F9Q engines: | |
Nominal | 48.00 mm + 0.02 mm |
Axial clearance of the crankshaft | 0.070 - 0.230 mm |
Thrust washer thickness | 2.30, 2.35, 2.40 and 2.45mm |
Lubrication system
Characteristic | Meaning |
Minimum oil pressure at 80°C: | |
At 1000 rpm | 1.2 bar |
Oil pump clearances: | |
Minimum | |
Between gear and housing | 0.100 |
Maximum | |
Between gear and housing | 0.240 mm |
Tightening torques, Nm
Characteristic | Meaning |
Valve cover nuts/bolts | 12 |
Camshaft bearing caps: | |
Fasteners with a diameter of 8 mm | 20 |
Fasteners with a diameter of 6 mm | 10 |
Camshaft gear bolt: | |
F8Q engines | 50 |
Nut of the mechanism of a tension of a gear drive belt | 50 |
Countershaft Gear Bolt - F8Q 620, F8Q 784 and F9Q 730 Engines | 50 |
Roller Bolt - All Other Engines | No data |
Nut of a cogwheel of the fuel pump | Contact the Head Power systems, release |
Oil nozzle mounting bolts | 20 ± 2 |
Flywheel mounting bolts* | 50 — 55 |
Pallet fixing bolts | 12 -15 |
drain plug | Contact the Head Maintenance |
Engine/Gearbox Mounts | Refer to Section 13 |
Reinforced Bracket/Flywheel Cover: | |
On the engine | 50 |
Wheel bolts | Contact the Head Maintenance |
Cylinder head bolts - F8Q 620, F8Q 788 and all F9Q** engines: | |
Stage 1 - all bolts, in the order shown in illustration 9.51 | 30 |
Stage 2 | Tighten all bolts 50°± 4° |
Stage 3 | Wait 3 minutes |
Stage 4 | Loosen bolts 1 and 2 completely |
Stage 5 | Tighten bolts 1 and 2 with a tightening torque of 25 Nm |
Stage 6 | Tighten bolts 1 and 2 by 213°± 7° |
Stage 7 | Loosen bolts 3 and 4 completely |
Stage 8 | Tighten bolts 3 and 4 with a tightening torque of 25 Nm |
Stage 9 | Tighten bolts 3 and 4 by 213°± 7° |
Stage 10 | Loosen bolts 5 and 6 completely |
Stage 11 | Tighten bolts 5 and 6 with a tightening torque of 25 Nm |
Stage 12 | Tighten bolts 5 and 6 by 213°± 7° |
Stage 13 | Loosen bolts 7 and 8 completely |
Stage 14 | Tighten bolts 7 and 8 with a tightening torque of 25 Nm |
Stage 15 | Tighten bolts 7 and 8 by 213°± 7° |
Stage 16 | Loosen bolts 9 and 10 completely |
Stage 17 | Tighten bolts 9 and 10 with a tightening torque of 25 Nm |
Stage 18 | Tighten bolts 9 and 10 by 213°± 7° |
Cylinder head bolts - F8Q 784 and F8Q 786* engines: | |
Stage 1 - all bolts, in the order shown in illustration 9.51 | 30 |
Stage 2 | Tighten all bolts 50°± 4° |
Stage 3 | Wait 3 minutes |
Stage 4 | Loosen bolts 1 and 2 completely |
Stage 5 | Tighten bolts 1 and 2 with a tightening torque of 25 Nm |
Stage 6 | Tighten bolts 1 and 2 by 213°± 7° |
Stage 7 | Loosen bolts 3 and 4 completely |
Stage 8 | Tighten bolts 3 and 4 with a tightening torque of 25 Nm |
Stage 9 | Tighten bolts 3 and 4 by 213°± 7° |
Stage 10 | Loosen bolts 5 and 6 completely |
Stage 11 | Tighten bolts 5 and 6 with a tightening torque of 25 Nm |
Stage 12 | Tighten bolts 5 and 6 by 213°± 7° |
Stage 13 | Loosen bolts 7 and 8 completely |
Stage 14 | Tighten bolts 7 and 8 with a tightening torque of 25 Nm |
Stage 15 | Tighten bolts 7 and 8 by 213°± 7° |
Stage 16 | Loosen bolts 9 and 10 completely |
Stage 17 | Tighten bolts 9 and 10 with a tightening torque of 25 Nm |
Stage 18 | Tighten bolts 9 and 10 by 213°± 7° |
Stage 19 | Start the engine and warm it up to normal operating temperature (fan should turn on) - then turn off the engine |
Stage 20 | Let the engine cool down completely |
Stage 21 | Tighten bolts 1 and 2 further by 120°± 7° |
Stage 22 | Tighten bolts 3 and 4 further by 120°± 7° |
Stage 23 | Tighten bolts 5 and 6 further by 120°± 7° |
Stage 23 | Tighten bolts 5 and 6 further by 120°± 7° |
Stage 24 | Tighten bolts 7 and 8 further by 120°± 7° |
Stage 25 | Tighten bolts 9 and 10 further by 120°± 7° |
Crankshaft Pulley Bolt: | |
Early engines | 90 — 100 |
Late belt driven engines "HTD2" - with tack compound on the thread: | |
Stage 1 | 20 |
Connecting rod bearing cap bolts | 45 — 50 |
Main bearing caps | 60 — 65 |
Oil pump bolts - F8Q 620, F8Q 784, F9Q 730 engines: | |
Bolts with a diameter of 6 mm | 10 |
Oil pump - all other engines: | |
Mounting bolts | No data |
* After starting the engine for the first time, it is not necessary to re-tighten the cylinder head bolts. |